A novel method to localize antibody-targeted cancer deposits intraoperatively using handheld PET beta and gamma probes
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Assessing cancer margins, lymph nodes, and small cancer deposits intraoperatively can be challenging. A new device has become available that allows the detection of positron emission tomography (PET) radiotracers through both high-energy gamma and short-range beta emissions. These PET probes are handheld, allowing for real-time evaluation of cancer using a tool that provides surgeons with better intraoperative assessment of tumor sites.
Within the context of two institutional review board (IRB)-approved protocols investigating new applications of antibody-labeled PET scanning, 124I-labeled humanized monoclonal antibodies specific for colorectal cancer (huA33) and renal tumors (cG250) were constructed. Patients underwent preoperative PET scans, approximately seven days post-tracer infusion, when tumor-to-nontumor ratios were high. Suspected tumor deposits were evaluated intraoperatively with handheld beta and gamma PET probes.
Handheld PET probes detected emissions from all tumors. Count rates from the gamma probe on tumor ranged from 48 to 306 cps, and for the beta probe ranged from 18 to 190 cps. Gamma and beta emissions exhibited a strong positive correlation. The ratio of gamma and beta counts was at least twice that of the background counts for all tumors evaluated.
This study is the first to demonstrate the utility of beta probes for the intraoperative detection of radiolabeled antibodies targeting cancer. Importantly, the recorded beta count rates from the beta probe correlate with the count rates from the high-energy gamma probe. Furthermore, the beta probe may offer superior specificity for real-time localization of small tumor deposits, compared to gamma probes. The intraoperative portable PET probe may prove a valuable bridge to combining tumor biology and PET technology to guide surgical therapy.
KeywordsPET probes Cancer Colorectal cancer Renal cell cancer Humans Novel Minimally invasive
Supported in part by a grant from the Society of American Gastrointestinal Endoscopic Surgeons (V.S.), and in part by the Ludwig Center for Cancer Immunotherapy and 5 PO1 Ca33049.
- 1.Alazraki NP, Mishkin FS (1991) Fundamentals of nuclear medicine, 2nd edition. The Society of Nuclear Medicine, Inc., ISBM? 0-932004-29-6, p 85Google Scholar
- 3.Essner R, Daghighian F, Giuliano A (2002) Advances in FDG PET probes in surgical oncology. Cancer J8:100–108Google Scholar
- 4.Gulec SA, Dahgighian F, Essner R (2006) PET Probe: Evaluation of technical performance and clinical utility of a handheld high-energy gamma probe in oncologic surgery. Ann Surg Oncol 1–8Google Scholar
- 7.Divgi CR, Pandit-Taskar N, Jungbluth AA, Reuter VE, Gonen M, Ruan S, Pierre C, Nagel A, Pryma DA, Humm J, Larson SM, Old LJ, Russo P (2007) Preoperative characterisation of clear-cell carcinoma using iodine-124-labelled antibody chimeric G250 (124I-cG250) and PET in patients with renal masses: a phase I trial. Lancet Oncol 8:304–310CrossRefPubMedGoogle Scholar